Er 19 Low

Biasi Er 19 Fault Code

Also written as ER19 — same fault.

The Biasi Er 19 fault code means: your boiler is having trouble measuring the temperature of the cold water coming in, which may affect how well it heats your hot water.. It appears on 2 Biasi models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Domestic hot water inlet probe failure (if present)
Typical repair cost £90-160 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Biasi models that show the Er 19 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Biasi Er 19 fault code information on this page is sourced and cross-checked against the official Biasi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026